Bright, vibrant images help educators communicate key points from their lessons, accurately present findings and research through graphs and PowerPoint and keynote presentations, and, most importantly, keep students engaged in the learning process. Projecting vibrant color is also important since 86% of content projected includes color according to a recent TFCinfo Projector Color Brightness Study.
Since technology purchasers rarely get the opportunity to see different projectors side-by-side, except maybe if they are visiting a tradeshow, it can be hard for them to know what they (and ultimately their students) are truly missing when they choose projectors with lower color brightness levels. This is why understanding the internal structure of a particular projector and its specifications are so important.
There are two major technologies used by projector manufacturers: 3-Chip LCD (or 3LCD) and 1-Chip DLP. All other technology makes up less than 3% of total market share according to PMA research for Q3 2015 for North America. By mixing the three primary colors (red, green, and blue) together in differing amounts, projectors can create virtually any color on the spectrum. The 3LCD technology projects these colors together simultaneously whereas the 1-Chip DLP technology projects the colors sequentially using a rotating color wheel.
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According to a whitepaper available on Epson’s website, “Examining Color Performance Between 3-Chip LCD and 1-Chip DLP Projection Technologies,” authored by Dr. Abhay Sharma, former chair of the International Color Consortium Working Group, users see the color white when all three primary colors overlap in any given projector system. The levels of projected white, also called White Light Output, are measured using lumens, and in the past this measurement was labeled as the projector’s “brightness” level. However, this single measurement, while it shows one aspect of a projector’s image quality – the projector’s brightness when projecting white – does not provide complete insight into the true image performance of a projector. When discussing image performance in today’s multimedia world, manufacturers must address the production of Color Light Output to ensure that video and images are projected with clear, vibrant color.
To understand a projector’s comprehensive color performance, users need to understand the inner-workings of the two major projector technologies mentioned above. As Dr. Sharma details in the whitepaper, 3LCD technology uses a system of dichroic mirrors and three individual chips to control the primary colors. The technology allows all three primary colors to illuminate the screen at the same time thus resulting in brighter, more colorful images compared to those images produced by 1-Chip DLP technology. That DLP technology does not simultaneously project all three colors, but instead it projects the colors in sequence through a single spinning wheel. When one color of the wheel is being projected, the other colors are being rejected (not passing through for projection), resulting in dimmer, less colorful images. The difference in 3LCD versus 1-Chip DLP technology is portrayed in the video at the bottom of this article.
This idea of color brightness can be visualized using color gamuts, which provide users three-dimensional representations that analyze the color response of different projectors. The 3LCD projector gamut has a much fuller volume, while the 1-Chip DLP projector has a smaller, lower overall volume. As mentioned, this is because 1-Chip DLP technology does not project colors simultaneously and therefore is not capable of creating the same range of colors as 3LCD systems, thus resulting in a smaller color gamut.
Published by the International Committee for Display Metrology (ICDM) in 2012, the Color Light Output specification provides a better way to assess a projector’s color light output capabilities. So instead of being satisfied with a single “brightness” specification – based on white brightness only – it is recommended that all users and buyers of projectors leverage the Color Light Output specification and look for the projector’s color bright¬ness when considering a new projector. If a projector does have two lumens specifications – one for white brightness and one for color brightness – then the color brightness of that projector is likely much lower than the stated white brightness.
With the right projector, teachers and students can display high definition content with higher quality in bright environments. However, without sufficient color brightness, images may be muddy, soft and lose detail, even in a dark room. This, in part, is why the Color Light Output specification is increasingly being added to projector bids issued by higher education institutions.
Given the investment involved in a new technology implementation – especially a large-scale implementation – it is important for technology purchasers to do their research: checking for color brightness and the Color Light Output specification in order to ensure getting the highest-performing projector to meet the teaching and learning needs of educators and students.
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